Furnace with Manifold for Controlling Supply of Heated Liquid to Multiple Heating Loops

ABSTRACT

A furnace includes a pump in a circuit through a heat exchanger and a manifold having a plurality of discharge openings in a first area and return openings in a second area connected by a transfer area with each discharge and return feeding a respective heat loop. A bypass in the circuit includes a temperature controlled protection valve connected between the bypass and the manifold. The heated liquid inlet of the manifold is connected to the manifold in the first area with the plurality of discharge openings at a position between the plurality of discharge openings and the plurality of return openings. The manifold is defined by a rectangular chamber divided longitudinally and diagonally by a transverse wall which terminates at one end at a position spaced from an adjacent end of the chamber to define an undivided portion of the chamber at the end which forms the transfer area.

This invention relates to a furnace and particularly to a manifold forthe furnace which provides connections for two or more liquid loops ordrops each for providing heating through a separate heat exchanger to aseparate area to be heated, where the manifold is arranged to controlthe supply of heated liquid from the furnace to the separate heatingloops. There may be only two loops or more loops depending on capacityand requirements.

The arrangement herein provides a simplified form of manifold which canbe mounted in the circuit in which the liquid, typically water, isheated in the heat exchanger of the furnace in order to supply theheated water to two or more loops.

The arrangement herein is particularly well suited for outdoor woodfurnaces or any exchanger where multiple buildings are heated.

SUMMARY OF THE INVENTION

According to the invention there is provided a furnace for heating aheat transfer liquid comprising:

a furnace heat exchanger having a heated liquid outlet and a cooledliquid return so that cooled liquid returned to the return passesthrough the furnace heat exchanger to be heated and discharged throughthe heated liquid outlet;

a heating system in the furnace for applying heat to the furnace heatexchanger to heat the liquid;

a furnace pump for pumping the liquid in a circuit through the furnaceheat exchanger;

a manifold connected in the circuit between the liquid outlet and liquidreturn;

the manifold having a heated liquid inlet for receiving the heatedliquid from the heated liquid outlet and a cooled liquid outlet forsupplying cooled liquid to the liquid return;

the manifold having a plurality of discharge openings and a plurality ofreturn openings;

the discharge openings being collected in adjacent positions in a firstarea of the manifold and the return openings being collected in adjacentpositions in a second area of the manifold with the first and secondareas being connected by a transfer area of the manifold for transfer ofliquid therebetween;

each discharge opening being associated with a respective return openingfor connection to a respective supply loop including a respective looppump and a respective output heat exchanger for heating a respectivezone with liquid being extracted from the manifold by the loop pumpthrough the respective discharge opening and returned to the respectivereturn opening;

the heated liquid inlet of the manifold being connected to the manifoldin the first area with the plurality of discharge openings at a positionbetween the plurality of discharge openings and the plurality of returnopenings.

In a preferred arrangement there is provided a bypass in the circuit forliquid to bypass the manifold together with a temperature controlledprotection valve connected between the bypass and the manifold, thevalve being operated to control flow between the manifold and the bypasssuch that when liquid at the cooled liquid return is below apredetermined temperature the valve operates to halt passage through themanifold and, as a temperature of the liquid increases, the valve isopened to allow passage through the manifold dependent on the increasingtemperature. In other words, when the liquid at the cooled liquid returnis below the predetermined temperature the valve operates to haltpassage from the manifold and, as the temperature of the liquidincreases, the valve is opened to allow passage through the manifoldback to the furnace dependent on the increasing temperature.

This arrangement therefore tends to reduce the amount of heated liquidavailable to be transferred to the separate loops. However the loopseach include their own separate pump so that the amount of water passingthrough each loop remains typically at a constant value. The manifoldtherefore provides a compensation arrangement where some of the waterreturned by the loop must pass to the discharge opening to that loopsince insufficient water is available from the circuit within thefurnace.

In addition the arrangement herein can provide the possibility for thetotal volume of liquid pumped through the loops to be different from thevolume passing through the circuit. Typically the volume passing throughthe loops is less than the available liquid from the circuit. However insome cases the available volume from the circuit may be less than thatwhich is taken by the loops.

Preferably the heated liquid inlet of the manifold is connected to themanifold in the first area separate from the transfer area between theplurality of discharge openings in the first area and the plurality ofreturn openings in the second area. In this way cooled water returningfrom the loops to the return openings of the manifold access the heatedliquid entering the heated liquid inlet to mix with that heated liquidbefore the mixed liquid reaches the discharge openings. This prevents amode of operation in which one of the discharge openings to one of theloops receives more heat than the other or others of the dischargeopenings. In this way the heat available in the heated liquid isbalanced between each of the loops.

Preferably the cooled liquid outlet is connected to the transfer area.

As stated above in many cases the sum of volumes pumped by the looppumps is different from a volume pumped by the furnace pump.

The arrangement is particularly effective where a sum of volumes pumpedby the loop pumps is greater than a volume pumped by the furnace pumpand allowed to pass through the manifold by the protection valve.

Preferably the protection valve is connected between cooled liquidoutlet of the manifold and the bypass and the protection valve controlsdischarge of liquid from the cooled liquid outlet of the manifold. Inthis arrangement preferably the protection valve is connected to themanifold at the transfer area.

In a particularly effective arrangement the manifold comprises a chamberdivided longitudinally by a transverse wall into the first area on afirst side of the wall and the second area on a second side of the walland wherein the transverse wall terminates at one end at a positionspaced from an adjacent end of the chamber to define an undividedportion of the chamber at said end which forms the transfer area.

In this arrangement the heated liquid inlet of the manifold ispreferably arranged on one side the transverse wall in the first area.

While other shapes can be used, preferably the chamber is rectangular incross-section to define four walls at right angles with the dischargeopenings in a first wall and the return openings in a second wall.

Where the chamber is rectangular, preferably the discharge openings arelocated in a first wall and the return openings in a second wall atright angles to the first wall with the transverse wall arrangeddiagonally to the first and second walls. In this arrangement preferablythe heated liquid inlet is located in a third wall and the cooled liquidoutlet is in a fourth wall.

Preferably there is a transfer channel for the heated liquid along thethird wall for carrying the heated liquid to the inlet therein.

According to a second aspect of the invention there is provided afurnace for heating a heat transfer liquid comprising:

a furnace heat exchanger having a heated liquid outlet and a cooledliquid return so that cooled liquid returned to the return passesthrough the furnace heat exchanger to be heated and discharged throughthe heated liquid outlet;

a heating system in the furnace for applying heat to the furnace heatexchanger to heat the liquid;

a furnace pump for pumping the liquid in a circuit through the furnaceheat exchanger;

a manifold connected in the circuit between the liquid outlet and liquidreturn;

the manifold having a heated liquid inlet for receiving the heatedliquid from the heated liquid outlet and a cooled liquid outlet forsupplying cooled liquid to the liquid return;

the manifold having a plurality of discharge openings and a plurality ofreturn openings;

the discharge openings being collected in adjacent positions in a firstarea of the manifold and the return openings being collected in adjacentpositions in a second area of the manifold with the first and secondareas being connected by a transfer area of the manifold for transfer ofliquid therebetween;

each discharge opening being associated with a respective return openingfor connection to a respective supply loop including a respective looppump and a respective output heat exchanger for heating a respectivezone with liquid being extracted from the manifold by the loop pumpthrough the respective discharge opening and returned to the respectivereturn opening;

wherein the manifold comprises a chamber divided longitudinally by atransverse wall into the first area on a first side of the wall and thesecond area on a second side of the wall and wherein the transverse wallterminates at one end at a position spaced from an adjacent end of thechamber to define an undivided portion of the chamber at said end whichforms the transfer area.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunctionwith the accompanying drawings in which:

FIG. 1 is an isometric view of a manifold of a furnace according to thepresent invention wherein the heating system which applies heat toliquid in a circuit is shown only schematically.

FIG. 2 is an isometric view from the opposite side relative to FIG. 1showing the furnace of FIG. 1 and including two heat transfer loopsconnected to the manifold which are again shown only schematically.

FIG. 3 is an end elevational view of the manifold of FIG. 1.

FIG. 4 is a cross-sectional view along the lines 4-4 of FIG. 3.

FIG. 5 is a cross-sectional view along the lines 5-5 of FIG. 3.

FIG. 6 is a front elevational view of the manifold of FIG. 1.

FIG. 7 is a cross-sectional view along the lines 7-7 of FIG. 6.

FIG. 8 is a cross-sectional view along the lines 8-8 of FIG. 6.

In the drawings like characters of reference indicate correspondingparts in the different figures.

DETAILED DESCRIPTION

In FIGS. 1 and 2 is shown a furnace 10 arranged for heating a heattransfer liquid filter communicates the liquid to different locationsfor heating zones to be heated by the furnace. The furnace comprises amanifold 11 which is connected to a furnace heat exchanger 12 within achamber 13 where the heat exchanger 12 receives heat from a heat sourceschematically indicated at 14 so as to apply heat to the transfer liquidwithin the heat exchanger 12. The furnace heat exchanger has an outlet15 and a cooled liquid return 16 so that the cooled liquid passesthrough the furnace heat exchanger 12 to be heated and dischargedthrough the outlet 15. A furnace pump 17 attached to the manifold 11 hasan inlet 18 for receiving the heated liquid and transferring the liquidthrough the pump after a rate determined by the pump into the manifold11. The manifold 11 further includes a return pipe 19 which carriescooled liquid and returns it through a shutoff valve 20 a coupling 21which feeds the cooled liquid back to the inlet 16.

This arrangement thus provides a circuit around which the liquid ispumped so as to pass through the heat exchanger 12 and to transfer heatfrom the source 14 into the liquid within the manifold 11.

The liquid is typically water often supplemented by anti-freezing agentsand other materials known to persons skilled in the art. However liquidscan be used which transfer heat from the source 14 to the areas to beheated.

The manifold 11 includes two discharge openings 22 and 23 from which theheated liquid within the manifold can be extracted and transferredthrough heating loops to two heat exchanges 24 and 25. Thus the heatexchanges are located on a respectable loop 26, 27 each of whichincludes a respective pump 28, 29 for transferring the liquid around theloop from the discharge opening 22, 23 back to a return opening 30A, 30Bat the manifold 11. The rate of flow of the liquid around the loops isdetermined by the pumps 28 and 29.

The manifold further includes a bypass duct 31 connected on a downstreamside 32 of the pump. At the inlet 18 to the pump is provided a shutoffvalve 33 which controls the entry of the heated water into the inlet ofthe pump. The bypass duct 31 is connected to a boiler protection valve34. Valves of this type are well known to persons skilled in the art andinclude a temperature controlled valve element 35 which allows water topass from the bypass 31 to the return duct 19. This flow is closed offas the temperature at the valve 34 increases and instead liquid is drawnfrom an outlet 36 of the manifold 11. In this way on startup of thefurnace while the liquid is not yet heated to the required temperature,all of the flow bypasses the manifold 11 through the bypass duct 31allowing the temperature of the heat transfer liquid to be rapidlyincreased by circulation through the heat exchanger 12. Only when thetemperature in the transfer liquid increases does the valve 34 open togradually close off flow through the bypass duct 31 while graduallyincreasing the flow from the outlet duct 36 of the manifold 11. Whenoperating at full temperature, the bypass duct 31 is fully closed by thevalve 34 and all flow passes through the manifold 11.

This boiler protection valve 34 thus protects the boiler by avoidingcontinual low temperatures within the heat exchanger 12 which coulddamage the heating system. However the boiler protection valve 34 is theonly such valve within the systems of the loops 26 and 27 contained nosimilar boiler protection valve as this is not required as explainedhereinafter.

The manifold 11 comprises a chamber 37 which is formed as a square orrectangular duct closed at both ends are 38 and 39. The duct is dividedinto two separate areas by a transverse wall 40 so as to form a secondarea of 41 above the wall 40 and the first area 42 below the wall 40. Asbest shown in FIG. 7 and eight, the wall 40 is a diagonal wall extendingfrom an apex between walls 43 and 44 of the chamber diagonally to anapex between walls 45 and 46 of the chamber. Thus each of the areas 41and 42 is generally triangular in cross-section and extends partly alongthe chamber from the end of 38 to a position spaced from the end of 39.

The end of the dividing wall 40 is shown best in FIG. 4 where to benoted that the end 47 is located in a position spaced from the end 39 ofthe chamber so as to form a transfer area 48 in the chamber 37 which isdefined by the full extent of the chamber 37.

In this way the manifold is divided into the second area 41 defined bythe front wall 43, the top wall 45 and the dividing wall 40. Themanifold also is divided into the first area 42 defined by the bottomwall 44, the rear wall 46 and the dividing wall 40.

As best shown in FIG. 7, the outlet ducts 22 and 23 are connected to thebottom wall 44 buddies into the first area 42. Also the return openings30A and 30B are connected into the front wall 43 of the manifold that isinto the second area 41 above the dividing wall 40.

The manifold 11 is thus divided by the diagonal dividing wall 40 intothe first area 42 at which the discharge openings are connected, thesecond area 41 into which the return openings are connected and thetransfer area 48 at the position in the chamber 37 beyond the end 47 ofthe wall 40. The discharge openings 22 and 23 are located at spacedpositions along the first area spaced from the end 47 of the wall andthus spaced from the transfer area. In the embodiment shown there aretwo such discharge openings corresponding to two transfer loops forheating two zones. However it will be appreciated that more than twodischarge openings can be provided in this first area at spacedpositions along the area. Symmetrically the return openings 30A and 30Bare connected at the front wall 43 again at spaced positions along thelength of the second area spaced from the transfer area defined by theend 47 of the transverse wall. Again that there can be more than twosuch return openings to correspond to the number of discharge openings.The discharge and return openings are longitudinally offset along themanifold, that is the discharge and return openings are staggered eachfrom the next, to provide space for suitable couplings of an arrangementwell known to a person skilled in the art.

As best shown in FIG. 4, the heated water from the pump 17 passes intothe outlet 32 which communicates the heated liquid either to the bypassduct 31 or to a transfer duct 50 which communicates the heated water tothe manifold 11. The transfer duct connects to a communication duct 51which carries the heated water along the rear of the manifold chamber 37to communicate the heated water into the first area 42 at the rear wall46 where an opening 53 is provided. Thus the opening 53 for the heatedwater into the manifold is located in the rear wall 46 communicatingwith the first area 42 at a position spaced longitudinally of the outletopenings 22 and 23 in a direction toward the end 47 of the dividing wall40. Thus the inlet opening 53 is located within the first area 42 at aposition spaced from the transfer area 48.

The cooled liquid entering the return duct 19 through the valve 34passes along an inlet coupling 54 of the valve 34 from the top wall 45of the chamber 37 out of position within the transfer area 48. The inletcoupling 54 includes a collar 55 surrounding a discharge opening 56 inthe top wall 45 so the collar projects downwardly into the manifoldundefined and open mouth 57 of the collar at a position adjacent thetransverse wall 40. However it will be appreciated that in otherarrangements the collar may not protrude downwardly as describedhereinbefore.

In the event that the total volume of liquid drawn from the manifold bythe two or more loops is different from the amount of liquid enteringand leaving the manifold in the heating circuit, this difference isaccommodated by movement of liquid in the manifold between the areas 41and 42 and through the transfer area 48.

In a situation where the sum of the volumes pumped by the loop pumps 28and 29 is greater than the volume of liquid entering the manifold fromthe inlet 53, this difference is taken up by liquid being pulled intothe first area 42 from the second area 41 through the transfer area 48.This liquid is drawn from the return openings 30A and 30B so this extraliquid passes along the second area 41 to the transfer area and thenenters the first area 42 to be pulled out of the discharge openings 22and 23 by the pumps 28 and 29.

As best shown in FIG. 4, the position of the inlet 53 is such that thecooled water turning from the second area 41 around the end 47 of thedividing wall 40 passes the inlet 53 before it reaches the dischargeopenings 23 and 22. In this way the cooled water which enters the area42 from the return openings is mixed with the heated water from theinlet 53 before it reaches the discharge openings at 23 and 22. Onreaching the first discharge opening 23 just beyond the inlet 53, theliquid is mixed to a constant temperature so that the liquid dischargingthrough the opening 23 is at the same temperature as the liquiddischarging through the opening 22.

In this way the manifold balances the liquid flow between the two ormore loops while ensuring that neither of the loops is starved of heat.This occurs whether the initial installation is arranged so that thetotal volume of the loops is greater than the total volume of theheating circuit or whether the volume of the heating circuit istemporarily reduced by the operation of the boiler protection valve 34.

The arrangement described herein and therefore provides a simplemanifold arrangement which effectively balances and controls the liquidmovement while providing a simple construction which can be readilymanufactured.

The arrangement can be readily and simply installed as the individualloops are of a simple construction without any necessity for controlvalves.

The arrangement provides for a temperature difference between the supplyand return of up to 50° on the primary distribution loops to deliverheat load at a much lower rate. The arrangement can ensure adequate flowand water temperature into the heat exchanger. The arrangement caneliminate the need to make manifold using plumbing fittings when settingup the multiple distribution loops for different buildings all zones. Inone embodiment the construction provides two supply ports and two returnports. However three or more ports cannot be used. The arrangementherein can enable the use of 1 inch underground pipe for much longerprimary distribution lines and still deliver the required heat load. Thearrangement herein can allow much smaller more economical pumps to beused on the distribution loops. The simple construction can enable asignificant reduction in the plumbing time and therefore the cost ofinstallation. These simple construction of the manifold may enable theinstallation without professional assistance again reducing the cost.

Since various modifications can be made in my invention as herein abovedescribed, and many apparently widely different embodiments of same madewithin the spirit and scope of the claims without department from suchspirit and scope, it is intended that all matter contained in theaccompanying specification shall be interpreted as illustrative only andnot in a limiting sense.

1. A furnace for heating a heat transfer liquid comprising: a furnaceheat exchanger having a heated liquid outlet and a cooled liquid returnso that cooled liquid returned to the return passes through the furnaceheat exchanger to be heated and discharged through the heated liquidoutlet; a heating system in the furnace for applying heat to the furnaceheat exchanger to heat the liquid; a furnace pump for pumping the liquidin a circuit through the furnace heat exchanger; a manifold connected inthe circuit between the liquid outlet and liquid return; the manifoldhaving a heated liquid inlet for receiving the heated liquid from theheated liquid outlet and a cooled liquid outlet for supplying cooledliquid to the liquid return; the manifold having a plurality ofdischarge openings and a plurality of return openings; the dischargeopenings being collected in adjacent positions in a first area of themanifold and the return openings being collected in adjacent positionsin a second area of the manifold with the first and second areas beingconnected by a transfer area of the manifold for transfer of liquidtherebetween; each discharge opening being associated with a respectivereturn opening for connection to a respective supply loop including arespective loop pump and a respective output heat exchanger for heatinga respective zone with liquid being extracted from the manifold by theloop pump through the respective discharge opening and returned to therespective return opening; the heated liquid inlet of the manifold beingconnected to the manifold in the first area with the plurality ofdischarge openings at a position between the plurality of dischargeopenings and the plurality of return openings.
 2. The furnace accordingto claim 1 wherein there is provided a bypass in the circuit for liquidto bypass the manifold and a temperature controlled protection valveconnected between the bypass and the manifold, the valve being operatedto control flow between the manifold and the bypass such that whenliquid at the cooled liquid return is below a predetermined temperaturethe valve operates to halt passage through the manifold and, as atemperature of the liquid increases, the valve is opened to allowpassage through the manifold dependent on the increasing temperature. 3.The furnace according to claim 1 wherein there is provided notemperature controlled protection valve in the loops.
 4. The furnaceaccording to claim 1 wherein the heated liquid inlet of the manifold isconnected to the manifold in the first area separate from the transferarea between the plurality of discharge openings in the first area andthe plurality of return openings in the second area.
 5. The furnaceaccording to claim 1 wherein cooled liquid outlet is connected to thetransfer area.
 6. The furnace according to claim 1 wherein a sum ofvolumes pumped by the loop pumps is different from a volume pumped bythe furnace pump.
 7. The furnace according to claim 1 wherein a sum ofvolumes pumped by the loop pumps is greater than a volume pumped by thefurnace pump and allowed to pass through the manifold by the protectionvalve.
 8. The furnace according to claim 1 wherein the protection valveis connected between cooled liquid outlet of the manifold and thebypass.
 9. The furnace according to claim 1 wherein the protection valvecontrols discharge of liquid from the cooled liquid outlet of themanifold.
 10. The furnace according to claim 1 wherein the protectionvalve is connected to the manifold at the transfer area.
 11. The furnaceaccording to claim 1 wherein the manifold comprises a chamber dividedlongitudinally by a transverse wall into the first area on a first sideof the wall and the second area on a second side of the wall and whereinthe transverse wall terminates at one end at a position spaced from anadjacent end of the chamber to define an undivided portion of thechamber at said end which forms the transfer area.
 12. The furnaceaccording to claim 11 wherein the heated liquid inlet of the manifold isarranged on one side the transverse wall in the first area.
 13. Thefurnace according to claim 9 wherein the chamber is rectangular incross-section to define four walls at right angles with the dischargeopenings in a first wall and the return openings in a second wall. 14.The furnace according to claim 11 wherein the chamber is rectangular incross-section to define four walls at right angles with the dischargeopenings in a first wall and the return openings in a second wall atright angles to the first wall with the transverse wall arrangeddiagonally to the first and second walls.
 15. The furnace according toclaim 14 wherein the heated liquid inlet is located in a third wall. 16.The furnace according to claim 15 wherein there is a transfer channelfor the heated liquid along the third wall for carrying the heatedliquid to the inlet therein.
 17. The furnace according to claim 15wherein the cooled liquid outlet is in a fourth wall.
 18. A furnace forheating a heat transfer liquid comprising: a furnace heat exchangerhaving a heated liquid outlet and a cooled liquid return so that cooledliquid returned to the return passes through the furnace heat exchangerto be heated and discharged through the heated liquid outlet; a heatingsystem in the furnace for applying heat to the furnace heat exchanger toheat the liquid; a furnace pump for pumping the liquid in a circuitthrough the furnace heat exchanger; a manifold connected in the circuitbetween the liquid outlet and liquid return; the manifold having aheated liquid inlet for receiving the heated liquid from the heatedliquid outlet and a cooled liquid outlet for supplying cooled liquid tothe liquid return; the manifold having a plurality of discharge openingsand a plurality of return openings; the discharge openings beingcollected in adjacent positions in a first area of the manifold and thereturn openings being collected in adjacent positions in a second areaof the manifold with the first and second areas being connected by atransfer area of the manifold for transfer of liquid therebetween; eachdischarge opening being associated with a respective return opening forconnection to a respective supply loop including a respective loop pumpand a respective output heat exchanger for heating a respective zonewith liquid being extracted from the manifold by the loop pump throughthe respective discharge opening and returned to the respective returnopening; wherein the manifold comprises a chamber divided longitudinallyby a transverse wall into the first area on a first side of the wall andthe second area on a second side of the wall and wherein the transversewall terminates at one end at a position spaced from an adjacent end ofthe chamber to define an undivided portion of the chamber at said endwhich forms the transfer area.
 19. The furnace according to claim 18wherein the heated liquid inlet of the manifold is arranged on one sidethe transverse wall in the first area.
 20. The furnace according toclaim 18 wherein the chamber is rectangular in cross-section to definefour walls at right angles with the discharge openings in a first walland the return openings in a second wall at right angles to the firstwall with the transverse wall arranged diagonally to the first andsecond walls.